The big baddie for the upcoming Avengers movie is likely to be Loki from the Thor movie. Though Loki did play a big part in forming the original Avengers by tricking the Hulk into fighting Thor, I thought that there may be other supervillains that could play the movie baddie. Here are the top 3:
1) Ultron — The Living Automaton. A well-known villain in Marvel comics, Ultron had fought various superhero groups such as the Fantastic Four and the Avengers. Immediately upon his creation by Henry Pym (Ant-Man), Ultron had developed an Oedipus Complex which bore an irrational hatred of his creator / father. And that hatred continued on to the rest of humanity. Ultron’s goal in life had always been to destroy and enslave mankind.
2) Thanos — The Mad Titan. Thanos was, perhaps, one of the most powerful villains in Marvel comics. He’s not from Earth, but from a civilization living in the moon of Titan, circling around the planet Saturn. His thirst for power had pushed him to conquer the known universe, which includes Earth. In the series, The Infinity Gauntlet, Thanos had succeeded in doing so with the aid of an ultra-powerful artifact.
3) Sub-Mariner — Namor, the Prince of Atlantis. Though not a conventional enemy and sometimes a member of the Avengers, the Sub-Mariner had carried a deeply seethed hatred for surface dwellers because of the pollution and destruction brought on to his underwater kingdom by the activities of humans. In one of his tirades against surface dwellers, Namor had attacked New York pitting him against the Fantastic Four. In the early years of the Avengers, Namor teamed-up with the Hulk for a showdown against Iron Man, Thor, Ant-Man, and the Wasp.